Near-infrared imaging method for the in vivo assessment of the biodistribution of nanoporous silicon particles

In the development of new nanoparticle-based technologies for therapeutic and diagnostic purposes, understanding the fate of nanoparticles in the body is crucial. We recently developed a multistage vector delivery system comprising biodegradable and biocompatible nanoporous silicon particles (first-stage microparticles [S1MPs]) able to host, protect, and deliver second-stage therapeutic and diagnostic nanoparticles (S2NPs) on intravenous injection. This delivery system aims at sequentially overcoming the biologic barriers en route to the target delivery site by separating and assigning tasks to the coordinated logic-embedded vectors constituting it. In this work, by conjugating a near-infrared dye on the surface of the S1MP without compromising the porous structure and potential loading of S2NPs, we were able to monitor the in vivo distribution of S1MPs in healthy mice using an optical imaging system. It was observed that particles predominantly accumulated in the liver and spleen at the end of 24 hours. Further quantification of S1MPs in the major organs of the animals by elemental analysis of silicon using inductively coupled plasma-atomic electron spectroscopy verified the accuracy of in vivo near-infrared imaging as a tool for evaluation of nanovector biodistribution.     

Antitumor efficacy of a thrombospondin 1 mimetic CovX-body

CVX-045 is produced by covalently attaching a thrombospondin 1 (TSP-1) mimetic comprising a peptidic sequence and a linker to the Fab binding site of a proprietary scaffold antibody. CVX-045 possesses the potency of the TSP-1-derived peptide, along with the advantageous pharmacokinetics of an antibody. Antitumor activity of CVX-045 was evaluated in human xenograft models alone and in combination with standard chemotherapies and targeted molecules. In A549 and A431 xenograft models, CVX-045 demonstrated significant (P < .05) antiangiogenic activity, reducing tumor microvessel density and increasing the levels of necrosis within treated tumors. In an HT-29 xenograft model, CVX-045 in combination with 5-fluorouracil significantly (P < .01) decreased tumor growth rate compared with vehicle, CVX-045, or 5-fluorouracil alone. Cotreatment of CVX-045 plus CPT-11 delayed progression of tumor growth from day 28 to 60. In contrast CVX-045 alone treatment did not delay the progression of tumor growth, and CPT-11 alone delayed progression of tumor growth to day 39. Cotreatment of CVX-045 with sunitinib extended the time to reach tumor load from day 26 to 40. In summary, CVX-045 exhibits significant antiangiogenic activity in several tumor models and enhances antitumor activity in combination with chemotherapy or targeted therapies. These data suggest future avenues for effective combination therapy in treating solid tumors. CVX-045 has recently completed a phase 1 trial in solid tumors where it has been well tolerated.     

Gender differences in plasma biomarker levels in a cohort of COPD patients: a pilot study

Rationale

Little is known about gender differences in plasma biomarker levels in patients with chronic obstructive pulmonary disease (COPD).

Hypothesis

There are differences in serum biomarker levels between women and men with COPD.

Objective

Explore gender differences in plasma biomarker levels in patients with COPD and smokers without COPD.

Methods

We measured plasma levels of IL-6, IL-8, IL-16, MCP-1, MMP-9, PARC and VEGF in 80 smokers without COPD (40 males, 40 females) and 152 stable COPD patients (76 males, 76 females) with similar airflow obstruction. We determined anthropometrics, smoking history, lung function, exercise tolerance, body composition, BODE index, co-morbidities and quality of life. We then explored associations between plasma biomarkers levels and the clinical characteristics of the patients and also with the clinical and physiological variables known to predict outcome in COPD.

Results

The plasma biomarkers level explored were similar in men and women without COPD. In contrast, in patients with COPD the median value in pg/mL of IL-6 (6.26 vs 8.0, p = 0.03), IL-16 (390 vs 321, p = 0.009) and VEGF (50 vs 87, p = 0.02) differed between women and men. Adjusted for smoking history, gender was independently associated with IL-16, PARC and VEGF levels. There were also gender differences in the associations between IL-6, IL-16 and VEGF and physiologic variables that predict outcomes.

Conclusions

In stable COPD patients with similar airflow obstruction, there are gender differences in plasma biomarker levels and in the association between biomarker levels and important clinical or physiological variables. Further studies should confirm our findings.     

Constitutive expression of FosB and its short form, FosB/SF, induces malignant cell transformation in rat-1A cells

We have established Rat-1A cell lines constitutively expressing c-Fos and the two products of the fosB gene, FosB and its short form, FosB/SF. The expressed proteins in the different stable transfectants have been characterized by immunofluorescence and immunoprecipitation analysis. Our results demonstrate that constitutive expression of FosB, like the constitutive expression of c-Fos and, to a lesser extent, FosB/SF, results in cells that grow to increased saturation densities and have the ability to grow in an anchorage-independent manner. Most important is the finding that expression of these proteins augments the tumorigenic potential of Rat-1A cells. These results show that both forms of FosB have a stimulatory effect on cell proliferation.     

Conformation and properties of DNA–(Lys33, Leu67)100–(Orn)20 complex: A nucleohistone model

The synthesis and characterization of the block copolypeptide (Leu⁶⁷, Lys³³)₁₀₀Orn₂₀, a synthetic model of histone, are reported. In neutral aqueous solutions, 80% of the etheropolypeptide block assumes an α-helical conformation, whereas the polyornithine block is in a random-coil conformation. In the association complexes with DNA, melting and titration experiments, as well as CD results, indicate that the polyornithine block interacts with DNA, whereas at least 2/3 of the lysine residues of the (Leu, Lys) moiety are excluded from the direct binding with DNA. CD spectra of the association complexes reveal significant differences from those obtained with DNA–polyornithine and DNA–polylysine complexes but substantial similarities with CD spectra of native and reconstituted nucleohistones. In contrast to DNA–polyornithine complexes, the CD spectra of the ternary complexes, copolypeptide–DNA–ethidium bromide, indicate a strong reduction of the dye intercalation. The low-angle x-ray diffraction pattern, reminiscent of that of chromatin, reveals the presence of a superstructure in these complexes. The results obtained are discussed in connection with the expected structural features of the model.     

Integrin mechanotransduction stimulates caveolin-1 phosphorylation and recruitment of Csk to mediate actin reorganization

To identify the role of caveolin-1 in integrin mechanotransduction, we exposed bovine aortic endothelial cells to 10 dyn/cm2 of laminar shear stress. Caveolin-1 was acutely and transiently phosphorylated with shear, occurring downstream of beta1-integrin activation as the beta1-integrin blocking antibody JB1A was inhibitory. In manipulating Src family kinase (SFK) activity with knockdown of Csk or type 1 protein phosphatase (PP1) treatment, we observed coordinate increase and decrease in shear-induced caveolin-1 phosphorylation, respectively. Hence, shear-stimulated caveolin-1 phosphorylation is regulated by SFKs. Shear-induced recruitment and phosphorylation of caveolin-1 occurred at beta1-integrin sites in a beta1-integrin- and SFK-dependent manner. Csk, described to interact with pY14-caveolin-1 and integrins, bound to an increased pool of phosphorylated caveolin-1 after shear corresponding with elevated Csk at beta1-integrin sites. Like caveolin-1, treatment with JB1A and PP1 attenuated shear-induced Csk association with beta1-integrins. Csk function was assayed with transfection of a caveolin-1 phosphorylation domain peptide. The peptide attenuated shear-induced association of Csk at beta1-integrin sites, as well as colocalization of Csk with paxillin and phosphorylated caveolin-1. Because integrin and Csk activity regulate cytoskeletal reorganization, we evaluated the role of this mechanism in shear-induced myosin light chain (MLC) phosphorylation. Knockdown of Csk expression was sufficient to reduce MLC diphosphorylation due to shear. Disruption of Csk-integrin association by peptide treatment was also inhibitory of the MLC diphosphorylation response. Together these data indicate that integrin activation with shear stress results in SFK-regulated caveolin-1 phosphorylation that, in turn, mediates Csk association at integrin sites, where it plays a role in downstream, shear-stimulated MLC diphosphorylation.     

Prostate epithelial stem cells

The prostate gland is the site of the most commonly diagnosed cancer in men in USA and UK, accounting for one in five of new cases of male cancer. Common with many other cancer types, prostate cancer is believed to arise from a stem cell that shares characteristics with the normal stem cell. Normal prostate epithelial stem cells were recently identified and found to have a basal cell phenotype together with expression of CD133. Preliminary data have now emerged for a prostate cancer stem cell that also expresses cell surface CD133 but lacks expression of the androgen receptor. Here we examine the evidence supporting the existence of prostate cancer stem cells and discuss possible mechanisms of stem cell maintenance.     

2-Alkoxydihydrocinnamates as PPAR agonists. Activity modulation by the incorporation of phenoxy substituents

Herein we describe a series of potent and selective PPARgamma agonists with moderate PPARalpha affinity and little to no affinity for other nuclear receptors. In vivo studies in a NIDDM animal model (ZDF rat) showed that these compounds are efficacious at low doses in glucose normalization and plasma triglyceride reduction. Compound 1b (LY519818) was selected from our SAR studies to be advanced to clinical evaluation for the treatment of type II diabetes.     

CTLA-4 blockage increases resistance to infection with the intracellular protozoan Trypanosoma cruzi

Recent studies have revealed an important role for CTLA-4 as a negative regulator of T cell activation. In the present study, we evaluated the importance of CTLA-4 to the immune response against the intracellular protozoan, Trypanosoma cruzi, the causative agent of Chagas' disease. We observed that the expression of CTLA-4 in spleen cells from naive mice cultured in the presence of live trypomastigote forms of T. cruzi increases over time of exposure. Furthermore, spleen cells harvested from recently infected mice showed a significant increase in the expression of CTLA-4 when compared with spleen cells from noninfected mice. Blockage of CTLA-4 in vitro and/or in vivo did not restore the lymphoproliferative response decreased during the acute phase of infection, but it resulted in a significant increase of NO production in vivo and in vitro. Moreover, the production of IFN-gamma in response to parasite Ags was significantly increased in spleen cells from anti-CTLA-4-treated infected mice when compared with the production found in cells from IgG-treated infected mice. CTLA-4 blockade in vivo also resulted in increased resistance to infection with the Y and Colombian strains of T. cruzi. Taken together these results indicate that CTLA-4 engagement is implicated in the modulation of the immune response against T. cruzi by acting in the mechanisms that control IFN-gamma and NO production during the acute phase of the infection.